The 'TRACK' mnemonic toggles tracking on and off. By default the virtual coordinates always track with the window size. If the window is resized, the entire plotting surface is still visible but all drawn items expand or shrink to fit. The option to turn size tracking off is:
In this mode, the size of drawn items never changes when the window is resized. If the window is made smaller than the virtual drawing surface, scroll bars appear (if permitted by the window creation flags). If size tracking is enabled (the default), it affects the 'VIRTUAL' mnemonic because any resizing of the window will force the virtual dimensions to match the window.